The present invention relates to an apparatus for analyzing particles for obtaining parameters relating to fluorescence (cumulative fluorescent intensity, area or roundness, degree of fluorescent emission portion, etc.), on the basis of fluorescence image signals from cells (particles) contained in a sample liquid such as blood and urine, and more particularly to an apparatus for analyzing particles to detect and analyze the fluorescence of cells stained by a fluorescent dye, by irradiating (illuminating) laser light for exciting fluorescence to a flat sample liquid flow in a flow cell for forming a flat sheath flow.
Relating to the apparatus of the present invention, hitherto is known an apparatus in a construction designed for obtaining more specific morphological (morphologic) information for individual particles, on the basis of optical signals obtained from parts of the particles to be analyzed, by optically scanning particles flowing in a sheath flow with a fine focused laser beam in the direction crossing the flow direction of the particles.
This conventional apparatus for analyzing particles employing a flow cell is constructed as shown in FIG. 1, in which a laser beam from a laser light source 100 is focused finely and irradiated to particles flowing in a sheath flow in a flow cell 106 in two dimensions is not obtained. That is, it does not possess resolution ability in the right angle direction to the particle flow direction, as compared with the method shown in FIG. 1 or the apparatus of the present invention described below, the information obtained about the particles is less, and precision is low.
On the other hand, the Japanese Laid-open Patent Hei. 1-270644 discloses an apparatus for analyzing particles capable of obtaining particle image information by scanning with a light beam in a direction crossing the passing (transmitting) direction of the particles, and detecting the light passing through the particles by a photo detector.
The Japanese Laid-open Patent Hei. 2-105041 is an improved version of the apparatus disclosed in the above patent 1-270644, and discloses an apparatus for measuring particles capable of receiving transmitted light by an array type photo detector disposed at a conjugate position with the particle to be detected.
The Japanese Laid-open Patent Sho. 52-113272 discloses an apparatus capable of obtaining chrominance (color) information and morphological information (area and shape) of cells, by scanning with a spot light using a flying spot tube, in the midst of passing of biological cell specimen through a flow cell.
According to the Japanese Laid-open Patent Sho. 62-254037, the flow cytometer is furnished with a streak imaging device, and detection of particles by this imaging device are executed almost simultaneously, and the imaging signal is processed only when matched with the predetermined characteristic value, that is, only particles with specific characteristic are imaged. As the imaging device, sampling imaging by using a one-dimensional image sensor is also disclosed.
The Japanese Laid-open Patent Hei. 3-123840 discloses a construction designed for determining a particle size distribution of an object on the basis of the two-dimensional image data obtained by imaging a moving object such as iron ore by a one-dimensional image sensor, and accumulating the one-dimensional image data.
In the U.S. Pat. No. 4,338,024 and the corresponding Japanese Patent Publication Hei. 3-52573, a flat sample liquid flow is formed, that is, a flat sheath flow is formed, and the particle image is taken.
The Japanese Patent Publication Sho. 63-22569 discloses an imaging method in an image fiber transmission path for enlarging or reducing a synthetic image at the reception side, by enlarging or reducing while keeping spatial distributions at both ends of an image fiber in similar forms (figure).
In the catalogue (J9011-29AOIOM) of fused optical fibers of HOYA-SCHOTT Co., optical fibers capable of enlarging and reducing taper-shaped images, and image processing using an image amplifier, tapered optical fiber, and CCD are disclosed.
The Japanese Laid-open Patent Hei. 2-196983 discloses a laser light source apparatus designed to focus (condense) an output light of a laser diode by using an optical fiber.
In the Japanese Laid-open Patents Hei. 4-72544 and Hei. 4-72545, a second light source (normally emitting) for particles, and imaging means (one-dimensional image sensor) aside from a first light source (pulse emission) for imaging particles, and imaging means (two dimensional image sensor) are used. In the disclosed apparatus for analyzing particle images, the second imaging region is in a line form, and the light from the second light source is emitted to the imaging region in a long elliptical form.
In these conventional general flow cytometers, the intensity of fluorescence emitted from the cell stained by a fluorescent dye is easily determined (obtained), but information about the fluorescence images such as fluorescence luminance distribution and area and roundness degree of fluorescent emission portion cannot be obtained.
In the apparatuses disclosed in the Japanese Laid-open Patents Hei. 1-270644, Hei. 2-105041 and Sho. 52-113272, since an optical beam is used in scanning, a special device is needed, and stable scanning is difficult.
The apparatus disclosed in the Japanese Laid-open Patent Hei. 3-123840 relates to an apparatus for measuring the particle size of iron ore or other materials charged into a blast furnace, the field of which is different from the present invention. Besides, nothing is mentioned about real time processing of accumulated image data, or determination (calculation) of parameters of area, roundness degree, luminance distribution, etc.
The Japanese Laid-open Patents Sho. 62-254037 and Hei. 3-123840 do not refer to flat passing of sample liquid flow. By forming a flat flow, the quantity of analysis can be increased.
In the U.S. Pat. No. 4,338,024 and the Japanese Patent Publication Hei. 3-52573, as mentioned above, forming of a flat sample liquid flow is mentioned, but the construction "comprising means for forming a flat sample liquid flow, a one-dimensional image sensor for issuing an imaging signal in every scanning, and processing means for processing signals and operating onn the basis of the imaging signals from the sensor" is not stated in any one of these seven publications.
Besides, in the Japanese Patent Publication Sho. 63-22569 and in the catalogue of fused optical fibers of HOYA-SCHOTT Co., use in the particle analyzing field is not mentioned.
The Japanese Laid-open Patent Hei. 2-196983 states nothing about use in the particle analyzing field by lowering the coherency of laser light.
The Japanese Laid-open Patents Hei. 4-72544 and Hei. 4-72545 disclose nothing about acquisition of more specific fluorescence information and morphological information of particles on the basis of imaging signals from the one-dimensional image sensor by scanning particles.